Mucosal dysplasia of gallbladder: isolated and adjacent lesions to carcinoma.

Isolated dysplasia was found in 46 (54 lesions) of 2,027 gallbladders, which were histologically studied by serial step sectioning. Average age of patients was 63.8 with a male-to-female ratio of 1 to 3. These lesions, excluding polypoid lesions of adenoma, were located most frequently in the fundus and body, showing flat granular or irregular appearance. As to the size, 68.6% were smaller than 1 cm in diameter (89% were smaller than 2 cm). Most mild dysplasias were found in small lesions less than 0.5 cm in diameter and moderate ones in lesions of less than 1.5 cm, though severe dysplasias were found in various sizes. Gallstones were found in 86.9% of the cases with dysplasia, and intestinal metaplasia and pseudopyloric gland metaplasis were found in 80.4% and 100%. Dysplasia adjacent to carcinoma was found in 46 of 110 cases (41.8%), and this change was frequently found in lesions at the early stage and well-differentiated carcinoma. It seems that mucosal damage caused by a stone and subsequent inflammation may be important in the histogenesis of intestinal metaplasia and dysplasia.